Storage device including dummy word lines and operating method thereof

Abstract

Disclosed is a storage device which includes a non-volatile memory device and a storage controller. Based on a program request for a target memory cell of a first stack, the storage controller provides a first program command to the non-volatile memory device, in response to determining that the number of programmed memory cells of a second stack is one or more. The second stack includes a first dummy word line and a second dummy word line disposed adjacent to an upper end and a lower end of the second stack, respectively. Based on the first program command, control logic applies a first voltage greater than a pass voltage to a dummy word line closer to the first stack and applies a second voltage smaller than the pass voltage to a dummy word line more.

What is claimed is: 
     
         1 . A storage device comprising:
 a non-volatile memory device including at least one memory block divided into a plurality of stacks arranged in sequence in a vertical direction; and   a storage controller,   wherein the storage controller is configured to, based on a program request for a target memory cell of a first stack among the plurality of stacks:
 determine that a number of programmed memory cells of a second stack among the plurality of stacks is one or more, and 
 based on determining that the number of the programmed memory cells of the second stack is one or more, provide a first program command to the non-volatile memory device, 
   wherein the second stack includes a first dummy word line and a second dummy word line arranged adjacent to an upper end and a lower end of the second stack, respectively, and   wherein control logic of the non-volatile memory device is configured to, based on the first program command:
 apply a first voltage, greater than a pass voltage applied to an unselected word line of the non-volatile memory device, to a dummy word line closer to the first stack from among the first and second dummy word lines, and 
 apply a second voltage, smaller than the pass voltage, to a dummy word line more distant from the first stack from among the first and second dummy word lines. 
   
     
     
         2 . The storage device of  claim 1 , wherein the control logic of the non-volatile memory device is configured to:
 apply the first voltage to the dummy word line closer to the first stack from (i) a first time point after a verification interval and before a program execution interval to (ii) a second time point in the program execution interval; and   apply the second voltage to the dummy word line more distant from the first stack from (i) a third time point after the verification interval and before the program execution interval to (ii) a fourth time point in the program execution interval.   
     
     
         3 . The storage device of  claim 2 , wherein each of the first time point and the second time point is after an initial word line setting interval and before the program execution interval. 
     
     
         4 . The storage device of  claim 1 , wherein the storage controller is configured to, based on a second program request, provide a second program command to the non-volatile memory device in response to determining that a programmed memory cell is absent from the second stack, and
 wherein the control logic of the non-volatile memory device is configured to, based on the second program command, apply the pass voltage to each of the first and second dummy word lines, during a program execution interval.   
     
     
         5 . The storage device of  claim 1 , wherein the non-volatile memory device is configured to program the at least one memory block in a top-to-bottom (T2B) manner,
 wherein the first stack is disposed above the second stack in the vertical direction, and   wherein the control logic of the non-volatile memory device is configured to apply the first voltage to the first dummy word line and to apply the second voltage to the second dummy word line.   
     
     
         6 . The storage device of  claim 1 , wherein the non-volatile memory device is configured to program the at least one memory block in a bottom-to-top (B2T) manner,
 wherein the second stack is disposed above the first stack in the vertical direction, and   wherein the control logic of the non-volatile memory device is configured to apply the first voltage to the second dummy word line and to apply the second voltage to the first dummy word line.   
     
     
         7 . The storage device of  claim 1 , wherein the first voltage is greater than a threshold voltage for turning on a dummy memory cell connected to the dummy word line closer to the first stack. 
     
     
         8 . The storage device of  claim 1 , wherein the second voltage is smaller than or equal to a threshold voltage for turning off a dummy memory cell connected to the dummy word line more distant from the first stack. 
     
     
         9 . The storage device of  claim 1 , wherein the target memory cell is connected to a selected word line and a first selected string, and
 wherein the control logic of the non-volatile memory device is configured to:   boost a channel voltage of an inhibit cell connected to the selected word line and a second selected string, by applying the first voltage to the dummy word line closer to the first stack during a program execution interval for programming the target memory cell; and   reduce leakage in the vertical direction through the first selected string, by applying the second voltage to the dummy word line more distant from the first stack during the program execution interval.   
     
     
         10 . The storage device of  claim 1 , wherein the storage controller includes:
 a program table configured to store program status information corresponding to the first stack and the second stack;   a dummy word line manager configured to determine whether the number of the programmed memory cells of the second stack is one or more, by referring to the program table; and   a command manager configured to generate the first program command and to provide the first program command to the non-volatile memory device, based on determining that the number of the programmed memory cells of the second stack is one or more.   
     
     
         11 . A storage device comprising:
 a non-volatile memory device including at least one memory block divided into a plurality of stacks arranged in sequence in a vertical direction; and   a storage controller,   wherein the storage controller is configured to, based on a program request for a target memory cell of a first stack among the plurality of stacks:
 determine that a combined number of programmed memory cells of a second stack and a third stack among the plurality of stacks is one or more, and 
 based on determining that the combined number of the programmed memory cells is one or more, provide a first program command to the non-volatile memory device, 
   wherein the second stack includes a first dummy word line and a second dummy word line disposed adjacent to an upper end and a lower end of the second stack, respectively,   wherein the third stack includes a third dummy word line and a fourth dummy word line disposed adjacent to an upper end and a lower end of the third stack, respectively, and   wherein control logic of the non-volatile memory device is configured to, based on the first program command:
 apply a first voltage, greater than a pass voltage applied to an unselected word line of the non-volatile memory device, to a dummy word line closest to the first stack from among the first to fourth dummy word lines, and 
 apply a second voltage, smaller than the pass voltage, to a dummy word line most distant from the first stack from among the first to fourth dummy word lines. 
   
     
     
         12 . The storage device of  claim 11 , wherein the control logic of the non-volatile memory device is configured to:
 apply the first voltage to the dummy word line closest to the first stack from (i) a first time point after a verification interval and before a program execution interval to (ii) a second time point in the program execution interval; and   apply the second voltage to the dummy word line most distant from the first stack from (i) a third time point after the verification interval and before the program execution interval to (ii) a fourth time point in the program execution interval.   
     
     
         13 . The storage device of  claim 11 , wherein the non-volatile memory device is configured to program the at least one memory block in a top-to-bottom (T2B) manner,
 wherein the first stack is disposed above the second stack in the vertical direction,   wherein the second stack is disposed above the third stack in the vertical direction, and   wherein the control logic of the non-volatile memory device is configured to apply the first voltage to the first dummy word line and to apply the second voltage to the fourth dummy word line.   
     
     
         14 . The storage device of  claim 13 , wherein the control logic of the non-volatile memory device is configured to apply the pass voltage to the second and third dummy word lines. 
     
     
         15 . The storage device of  claim 11 , wherein the non-volatile memory device is configured to program the at least one memory block in a bottom-to-top (B2T) manner,
 wherein the second stack is disposed above the third stack in the vertical direction,   wherein the third stack is disposed above the second stack in the vertical direction, and   wherein the control logic of the non-volatile memory device is configured to apply the first voltage to the second dummy word line and to apply the second voltage to the third dummy word line.   
     
     
         16 . The storage device of  claim 15 , wherein the control logic of the non-volatile memory device is configured to apply the pass voltage to the first and fourth dummy word lines. 
     
     
         17 . The storage device of  claim 11 , wherein the first voltage is greater than a threshold voltage for turning on a dummy memory cell connected to the dummy word line closest to the first stack. 
     
     
         18 . The storage device of  claim 11 , wherein the second voltage is smaller than or equal to a threshold voltage for turning off a dummy memory cell connected to the dummy word line most distant from the first stack. 
     
     
         19 . An operating method of a storage device, wherein the storage device includes (i) a non-volatile memory device including at least one memory block divided into a plurality of stacks arranged in sequence in a vertical direction and (ii) a storage controller, the method comprising:
 determining, by the storage controller, whether a number of programmed memory cells of a second stack among the plurality of stacks is one or more, based on a program request for a target memory cell of a first stack among the plurality of stacks,
 wherein the second stack includes a first dummy word line and a second dummy word line disposed adjacent to an upper end and a lower end of the second stack, respectively; 
   providing, by the storage controller, a first program command to the non-volatile memory device, in response to determining that the number of the programmed memory cells is one or more;   applying, by control logic of the non-volatile memory device, a first voltage higher than a pass voltage to a dummy word line closer to the first stack from among the first and second dummy word lines, based on the first program command, wherein the pass voltage is a voltage applied to an unselected word line of the non-volatile memory device; and   applying, by the control logic of the non-volatile memory device, a second voltage lower than the pass voltage to a dummy word line more distant from the first stack from among the first and second dummy word lines, based on the first program command.   
     
     
         20 . The method of  claim 19 , wherein the storage controller includes a program table,
 wherein the program table is configured to store program status information corresponding to the first stack and the second stack, and   wherein determining whether the number of the programmed memory cells of the second stack is one or more comprises:   obtaining, by the storage controller, program status information corresponding to the second stack, by referring to the program table; and   determining whether the program status information corresponding to the second stack indicates whether the number of the programmed memory cells of the second stack is one or more.